Joss Whedon is staking his claim to another female superhero. Warner Bros. is on the verge of lassoing the Buffy the Vampire Slayer mastermind to write and direct the studio’s long-gestating Wonder Woman feature film, TV Guide Online has learned. The almost-done deal comes just two months after Whedon announced that he was getting out of the TV biz to focus on making movies, beginning with his forthcoming Firefly flick, Serenity.